ZINC SUPPLEMENTATION, MENTAL-DEVELOPMENT AND BEHAVIOR IN LOW-BIRTH-WEIGHT TERM INFANTS IN NORTHEAST BRAZIL

Objective: To test whether zinc supplementation reduces the deficits i n mental development and behaviour that are found in term infants of l ow birth weight in the study population. ' Design: A prospective doubl e-blind, part-randomised efficacy trial. Setting: A low-income populat ion in Pernambuco, northeast Brazil, where the economy is largely depe ndent on sugar-cane production, and where over 90% of deliveries occur in health facilities. Subjects: During a 20-month period, all singlet on, term infants weighing 1500-2499 g born to families of low income ( < US $280/month) were enrolled at birth (n = 205). At 6 and 12-months , the numbers tested were 163 and 138 respectively. Intervention: Infa nts born from January 1993-January 1994 were randomly assigned to rece ive daily, except Sundays, a placebo (n = 66) or 1 mg zinc (n = 68). T hose born February-August 1994 were given 5 mg zinc (n = 71). Suppleme ntation was for eight weeks, starting at birth. Field workers visited each infant at home to administer the supplement. Results: At 6 and 12 -months, mental and psychomotor development was assessed with the Bayl ey Scales of Infant Development and no significant differences in the scores of the three groups were found. At 12-months, behaviour was als o assessed on 5 ratings. Ratings were highest in infants given 5 mg zi nc (P = 0.042). Conclusions: Zinc supplementation (5 mg/d) for eight w eeks may reverse some of the poor behaviours, particularly responsiven ess, exhibited by low birth weight infants. No amelioration of their m ental and psychomotor deficits was found. Sponsorship: The Wellcome Tr ust, United Kingdom, provided financial support (Grant no. 036605/Z/92 ). Dr Lira was supported by GAPES (Fundacao Coordenacao de Aperfeicoam ento de Pessoal de Nivel Superior), Brazil. Descriptors: zinc suppleme ntation; infant development; behaviour; low birth weight.